Biacetate of anthrapurpurin and process of making same.



U ITED STATES PATENT OFFICE.

HERMANN VIETH, OF LUDWIGSHAFEN, GERMANY, ASSIGNOR TO KNOLL & COMPANY, OFSAME PLACE.

BiACETATE OF ANTHRAPURPURIN AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 678,070, dated July 9,1901.

Application filed December 8, 1900. Serial No. 39,118. (Specimensdpurpurinand Process of Making the Same,

of which the following is a specification.

-Recentinvestigation has shown that nearly all drugs used as purgativescontain certain derivatives of oxyanthraquinone as their activeprinciple. I have found that these purgatives may be substituted toadvantage by anthrapurpurin compounds having a close relation to theaforesaid oxyanthraquinoneglycosids. Especially the biacetateofanthrapurpurin hitherto unknown has proved to be a very usefulpurgative, being insoluble in the stomach and exercising a mild action,similar to that of aloes, in the alkaline intestines or bowels.

It has been found that the biacetate will be the suitable form foradministering the remedy, which if not changed would prove 5 to be unfitfor use on account of the intensive coloring of the urine. Thetriacetate as described by Perkin is far more difficultly soluble andreacts,therefore,too weakly. The ether of biacetate of anthrapurpurin,hitherto 3 unknown, will be produced by the reaction of the calculatedquantity of a means of acetylization on the anthrapurpurin. In using agreater quantity or an excessive quantity of the means of acetylizationon the anthrapurpurin this acetylization will proceed or continue up tothe triacetate, if care is not taken to allow the excess (the thirdmolecule) of the means of the acetylization to remain without effect,for instance, by the addition of a 4 diluting means or by themaintainance of a lower temperature. The said biacetate ofanthrapurpurin is a microcrystalline yellow powder having a fusing-pointof 175 to 178 centigrade, insoluble in water, readily soluble in boilingacetic acid and less soluble in alcohol. Caustic and carbonized alkalieswill gradually decompose the biacetate, forming a violet-blue solutionof anthrapurpurin.

The biacetate of anthrapurpurin, which is the subject of my invention,can be obtained by applying all the commonly-used methods ofacetylization upon anthrapurpurin. Hereunder some examples are given.

First. A mixture of five parts of anthrapurpurin and five to six partsof anhydric acetic 'acid is heated and kept boiling for about two tothree hours. Thenthe mass is allowed to crystallize, the crystals areseparated from the liquor, washed by alcohol, and dried. The product maybe purified by recrystallization 6o fromchlor'oform or acetic'acid. Theyield of anthrapurpurin biacetate is almost equal'to theory.

Second. Five parts of anthrapurpurin are put together with five parts ofacetic chlorid and ten parts of acetic acid, and this mixture" istreated as above.

Third. Five parts of anthrapurpurin are puttogether with'ten' parts ofacetic acid and three parts of oXychlorid of phosphorus, and thismixture is treated as above.

The analysis of the new product (five grams decomposed by fifty cubiccentimeters normal alkali) shows the following result:

7 Obtained. Calculated. Acetic acid: (1) 1.86 gr. 1.77 gr. 2) 1.82 gr.1.77 gr.

The purgative dose is 0.5 to one gram.

\Vhat I claim as myinvention is 36 1. The process for the production ofbiace= tate of anthrapurpurin consisting in treating anthrapurpurin withcalculated quantities of acetylizing reagents adapted to producebiacetate of anthrapurpurin, substantially as here- 5

